Chandrasekhar-mass WDs that explode in the SD scenario by detonation alone, without deflagration to detonation transition, produce too much \(^{56}\) Ni to be compatible with observations of normal SNe Ia. However, there are some super-Chandrasekhar-mass WDs that do have larger than usual \(^{56}\) Ni masses (e.g., [1]}, [2]} for recent studies).
Moreover, in a recent study [3]} argue that a Chandrasekhar-mass merger product that explodes within a short time after merger, namely, a short MED time, might have a different density structure than a Chandrasekhar WD in the SD scenario (be more extended), and therefore has different properties at explosion. Specifically, [3]} find that their calculated synthetic spectra of a merger product that explodes by detonation (with no deflagration to detonation transition) with \(t_{\rm MED}= \simeq 100 {~\rm yr}\)  in the DD scenario matches normal SN spectra.
Future studies should examine the properties of detonation of Chandrasekhar-mass WDs with MED times of up to \(t_{\rm EMD} \simeq 10^4 - 10^5 {~\rm yr}\) , and determine whether they produce normal or peculiar SNe Ia.
